Elaboration and characterization of new membranes based on the electropolymerization of mixtures of pyrrole and 4,4′-bis[N-(1-oxo)hexylpyrrole]dibenzo-18-crown-6 monomers

New membranes have been prepared by the electropolymerization of a new pyrrole dibenzo-18-crown-6 monomer with the pyrrole. The results present the characterization of the membrane recognition properties in the presence of different electrolytes. Films present a sensitivity to divalent cations like Ca2+, Mg2+ or Cu2+ owing to the crown ether function. Potentiometric measurements have allowed to quantify the membrane selectivity toward divalent cations in presence of Na+.

Dense new membranes of around 20 µm thickness, which bear macrocyclic crown ether moieties (PyEC) can be obtained by electropolymerization of the monomers Py and PyEC on a stainless steel gauze. Due to the specific complexing interactions, these membranes present a recognition for several ions, especially for the earth-alkaline cations. The potentiometric detection of Mg2+, Ca2+ and Cu2+ in presence of the Na+ i nterfering ion is possible despite a detection limit rather high du to the sodium interference. Nevertheless, experiments have allowed to show that the membrane is between 10 to 100 times more selective to divalent cations than to Na +.